1. Field of the Invention
The present invention relates to a method for providing a number portability of a mobile phone, and in particular to a method for providing a number portability of a mobile phone, in which a mobile phone subscriber is capable of freely changing a mobile phone service provider without changing a mobile directory number (MDN) using a number portability database which supports a multi-protocol.
2. Description of the Background Art
When a subscriber receives a mobile communication service from a mobile phone service provider for the first time, the mobile phone service provider designates a MSIN (Mobile Station Identification Number) and a MDN (Mobile Directory Number).
Here, the MSIN is a number used by the mobile phone service provider for inherently identifying a subscriber/terminal, and the MDN is a mobile directory number of a mobile phone subscriber.
If the subscriber wants to change to a new mobile phone service provider, the subscriber has to discard the MDN provided by the old mobile phone service provider and receive a new MDN from a new mobile phone service provider.
However, it is not that easy to change the MDN. In addition, the subscriber has to inform the change of MDN to the people around him, thereby causing much inconvenience.
Therefore, if the old MDN could be directly used without changing to a new MDN, it would save much trouble when the subscriber changes a mobile phone service from provider.
The method for exchanging the MDN between the mobile phone service providers consists of a number portability providing method of a mobile phone which uses an ANSI-41 protocol and a number portability providing method of a mobile phone which uses a GSM protocol.
The number portability providing method is used between the service providers which use the same core network protocol, so that it is possible to provide a number portability service to the mobile phone subscriber. However, in this case, it is impossible to provide a number portability service for the mobile phone service providers having different protocols.
The above problem may be overcome by building the number portability database by the kinds of the protocol although it is difficult to maintain the consistency of the data between the number portability databases. In addition, it is too expensive to implement the above matters.
The technique for providing the service provider number portability of a local phone is mainly divided into a technique implemented based on a switch and a technique implemented based on an intelligent network. The switch-based method is classified again into an onward routing method and drop-back method. Also, the intelligent network method is classified into a query on release method for inquiring to the database concerning the moved call and an all call query method for inquiring to the database concerning all calls made.
When adapting the provider number portability service to a local phone service, the most appropriate method for the local country communication environment is selected as a local country standard method.
Meanwhile, when the number portability service is provided between the local phone service providers, it affects other network service providers. In other words, in case a dialing network is a mobile phone network, not a local phone network. Therefore, the dialing network service provider may process the number portability in accordance with the all call query method. Here, in order to provide a service provider number portability of the local phone number, the mobile phone service provider must build a number portability database.
As another example, in the case that the number portability is provided based on the intelligent network method, since different intelligent network protocols (INAP, CAP/WIN) are used between the local phone network and the mobile phone network, the number portability database built in the local phone network is not used in the mobile phone network. In order to provide a service provider number portability of a local phone, the number portability database must be built for the local phone service provider, and the mobile phone service provider must additionally build the number portability database as well.
Accordingly, it is an object of the present invention to provide a method for providing a number portability of a mobile phone which is capable of providing a number portability service between mobile phone service provider networks having different protocols using a number portability database which supports a multi-protocol.
To achieve the above object, there is provided a method for providing a number portability of a mobile phone which includes a first step for transferring an enquiry message to a number portability database which supports a multi-protocol using an intelligent network protocol in a dialing network when a mobile phone of a called subscriber connected is identified as a number portability service destination at a gateway switch of a dialing network, a second step in which the number portability database recognizes the kind of an intelligent protocol of an enquiry message and calls a number portability service logic which supports a corresponding protocol, a third step for searching a number portability routing table based on the called number portability service logic, obtaining a routing information of the mobile phone of the called subscriber, processing a response message including the routing information based on the same protocol as the protocol of the dialing network and transferring to a gateway switch of the dialing network analyzes a routing number from the routing information forms an ISUP message for analyzing a routing number from the routing information and setting a call, and transfers a corresponding ISUP message to the gateway switch of the mobile phone network of the other mobile phone service provider so that the call may be transferred to the transfers a call to the mobile phone of the called subscriber subscribed to the mobile phone network of the other mobile phone service provider.